Coffee, caffeine and hemostasis: a review.

The effects of coffee and caffeine on haemostatic variables are reviewed. The potential relationship between coffee and cardiovascular disease warrants the study of possible links between coffee and haemostasis. The presently available evidence in favour or against such an association, however, is not very convincing and sometimes even conflicting. The findings on fibrinogen level and platelet in vivo activation as measured by plasma beta-thromboglobulin, seem to be the most reliable. If anything, these reports indicate an unfavourable effect of coffee, i.e. coffee may enhance thrombotic tendencies. Before more definite conclusions on the interference of coffee use with the haemostatic system can be made, more data are needed. In particular, randomized studies of coffee and caffeine intake in humans are indicated to assess the impact and the potential significance of coffee in such quantities as are commonly used by millions of people.